I live in Norway, where many people wear heavy pvc raincoats in rain, or even if it's broadcasted rain that day, and full rainwear if they are riding their bike, so that makes my life easier than in other countries, when it comes to wearing rainwear in public. A couple of years ago I started wearing pu/pvc rainwear outside. I only had courage to wear rainwear in dark black, blue or green. Actually, there were a couple of times where people stared weirdly at me. In hindsight, I believe it was because I was wearing jacket and pants in same colour. This makes a bit strange appearance, as it may look somehow like a uniform. Probably, they were wondering what I was up to, which company I was working for, or something like that. So my advice would be: If you want to seek as little attention as possible, try pairing upper and lower part with different colours, for example green upper and black lower part. In that way you will get a more casual look.
Another interesting thing has happened lately. Two years ago I came out as trans non-binary. That opened the opportunity for me to experiment with feminine outfits. The raincoats I once found attractive on women, I now wear publicly myself. I believe that since I wear feminine rainwear outfits, my rainwear is more "masked". Before people may have thought: "look at that guy wearing heavy rainwear, and it's hardly raining," while they now may think: "look at that person wearing a feminine outfit. A bit uncommon, but I guess I should be supportive, given the time we live in ..." etc, etc. The fact that it's a rainwear outfit is in that way forgotten. Of course, most likely, they don't think anything at all.
Also, the fact that I'm queer makes me even more careless of what people think of me. I'm trans, I wear dresses, I might as well wear rainwear. Actually, it has changed to such a degree that I enjoy when people look (to an exhibitionistic degree). They probably stare at me because I'm so pretty
A very wise person (my girlfriend) once said: you look pretty in an outfit if you feel pretty in it. So wear whatever you want with confidence, and you will shine like a star. Especially in shiny rainwear 